In response to changes in fuel formulations which have resulted in increased fuel volatility and vapor pressure, Stant has invented the PRE-VENT® fuel cap. Pre-Vent represents the latest in fuel cap technology and is designed to permit the controlled release of fuel tank pressure from volatile fuels. While removing the cap to refuel, a 1/2 turn of the Pre-Vent cap releases the fuel tank pressure into the atmosphere before the cap's sealing gasket is released from the filler neck. This feature dramatically reduces the possibility of fuel expulsion from the filler neck when the cap is removed.

Pre-Vent caps are also available in locking gas cap versions. The Pre-Vent locking gas cap gradually depressurizes the fuel system when the key is inserted into the lock cylinder.